there is the 'offical' spektrum ar640 that retails for 60.00
then there is teh targethobby.com brick the retails for 20.00 and is of questionable origin and lower (but seemingly, reliable) quality.
guts generally refer to ar6400, 1 external servo and 1 brushed motor and prop.

Ok! Now I have some UM Sukhoi guts and I bought a second servo for it, so that puts me at $41. Guess it'll be the $45 dollar challenge now!

I decided to build the Axis V4 by Scott Neeman, (Here) as an attempt at a mild 3D plane. I'm not much of a 3D pilot yet, but that's why I want to make a 3D plane to practice on!

I printed out the plans taped them together, and had at it with a razor blade. I ended up with an airframe that was too heavy, so I took another shot at it and the second attempt was lighter. I'll take pictures soon.

Then I installed the Suk motor, and did a thrust test. I could hover at half throttle! Pretty good for a first attempt. I still have about 8 grams of weight to add with the two aileron servos and pushrods, but that's fine. I'm expecting the weight W/O battery to be about 36 grams, and weight with 160 MAH 1 Cell to be 40 g.